Data processing and transmission system and method

ABSTRACT

A data processing and transmission system (1) for a numerical control unit (2) adapted to control a machine tool (3), comprises at least one input channel (4) adapted to a transit of operational signals from or to devices present in the machine tool, electronic circuits configured to process the operational signals to make available on an output interface (5) control signals for the numerical control unit, a multipolar cable (8) having a first and a second end, each provided with a multipolar connector (9), a master unit having the output interface, a main processor, a memory and at least one socket (7A) configured to be coupled to one of the multipolar connectors, one or more slave units (6), each provided with at least one external port (6A) defining the input channel, a memory, a secondary processor, and provided also with a first socket (6B) and a second socket (6C), configured to be coupled at least to a first or a second connector of the multipolar connectors in order to interconnect the slave unit at least with the master unit. The master unit has a clock and each slave unit has its own clock. The main processor of the master unit generates a synchronization signal and transmits it through the multipolar cable in order to synchronize all the clocks of the slave units with the clock of the master unit.

The present invention relates to a data processing and transmissionsystem and method. More specifically, the invention relates to a dataprocessing and transmission system for a numerical control unit adaptedto control a machine tool.

The environment in which the machine tool works, that is, the area wherethe mechanical pieces are machined, is typically “polluted”, with a highlevel of dirt (coolants, swarf, . . . ) and noise; however, the controlunit (CNC, Computer Numerical Control) is generally located in anelectrical panel outside the work area, in a “clean” environment, thatis, relatively protected.

The numerical control unit detects in real time measurements of themechanical piece being processed and machine parameters (for exampletemperature, imbalance of rotary tools, acoustic emissions) and/orcontrols actuators located in the machine tool, for example for movingbalancing weights or carriages. For that purpose, devices are present inthe machine tool, such as sensors and/or actuators, adapted to exchangeoperational signals with the control unit. For example, the control unitreceives data detected by the sensors and/or transmits control signalsto the actuators.

In many cases, it is necessary for one or more of these devices to bepositioned in the polluted environment.

In this context, a data processing and transmission system is used,operatively interposed between the control unit and the devices.

It should be noted that, in this context, there is an increasing requestfor flexibility in the data processing and transmission system.

In fact, the dimensions of machines are being reduced to allow the useof spaces to be optimised; there is often the need to place twodifferent machine tools for machining, whereas previously there was asingle machine. In addition, there is an increased request formulti-operation machines with mixed technology (for example to performgrinding and turning operations in the same machine).

All this determines the need for flexibility, with the possibility ofadapting the data processing and transmission system to the managementof different functions.

It should also be noted that the checking performed by the numericalcontrol unit may be basically of two types with respect to the actionsperformed by the machine tool to be checked: post-process or in-process,depending on whether the checking takes place, respectively, after theaction performed by the machine or during the machining with feedback onthe machine.

If an in-process checking is performed, it is particularly important andcritical to satisfy the need for managing in real time the exchange ofinformation between the control unit and the devices.

Another need is that of synchronising the operational signals exchangedbetween the data processing and transmission system and the devices;this synchronisation problem may be dealt with according to variousapproaches, depending on the architecture of the system.

In this regard, it should be noted that the prior art teaches the use ofcentralized intelligence data processing and transmission systems. Inthese solutions, the processing hardware of the data processing andtransmission system is concentrated in a single apparatus, that ispositioned in the electrical cabinet and has a plurality of ports for aparallel connection with the various devices by respective cables. Inthis approach, all the operational signals are connected to the singleapparatus, and the synchronisation occurs inside the apparatuses.

However, the concentrated intelligence data processing and transmissionsystems have several drawbacks.

A first drawback is due to the fact that the apparatus is bulky and notvery flexible, in the sense that it has predetermined dimensions andnumber of ports which cannot be adapted to the specific application;this means that the apparatus is generally over-sized for a specificapplication.

A further drawback is due to the installation difficulty, due to thehigh number of cables to be connected to the apparatus.

Moreover, the distance between the devices and the processing hardwareis the cause of not insignificant noise and has a negative effect on theaccuracy of the checking.

It should be noted that there are also prior art solutions which use asubstantially distributed intelligence architecture for the dataprocessing and transmission system.

However, these solutions do not provide a particularly effective answerto the needs described above, and have further drawbacks andlimitations.

A first drawback is due to the fact that they do not allow an effectiveand simple synchronisation of the data. Another difficulty of thesesystems is linked to the correlation of the data acquired by the variousdevices.

Another limitation of such systems is linked to the reliability, interms of continuity of service and the possibility of preventing faultsand malfunctions.

The aim of the present invention is to provide a data processing andtransmission system and method for a numeral control unit adapted tocontrol a machine tool which overcome the above-mentioned drawbacks ofthe prior art.

More specifically, an aim of the present invention is to provide a dataprocessing and transmission system and method which are particularlyflexible, which can be adapted simply to the different requirements ofuse.

Another aim of the present invention is to provide a data processing andtransmission system and method which allow the noise to be reduced andthe accuracy of the checking to be increased.

Another aim of the invention is to provide a data processing andtransmission system and method which simplify installation.

Another aim of the present invention is to provide a data processing andtransmission system and method which allow a simple and effectivein-process checking to be performed.

Another aim of the invention is to provide a data processing andtransmission system and method which are particularly reliable.

Another aim of the present invention is to provide a data processing andtransmission system and method which allow a particularly simple andeffective data synchronising.

These aims are fully achieved by the data processing and transmissionsystem and method for a numeral control unit adapted to control amachine tool according to the present invention and as characterised inthe appended claims.

The data processing and transmission system is adapted to be connectedto at least one device present in the machine tool. The device may be asensor (with relative transducer) or an actuator. More specifically, thedata processing and transmission system is adapted to be connected to aplurality of devices such as sensors and/or actuators.

The system comprises at least one input channel adapted to a transit ofoperational signals from or to devices present in the machine tool.Moreover, the system includes electronic circuits configured to processthe operational signals to make available on an output interface controlsignals for the numerical control unit.

The data processing and transmission system is equipped with amultipolar cable having a first and a second end, each provided with amultipolar connector.

Moreover, the processing and transmission system has a master unit,equipped with a main processor, a memory and at least one socketconfigured to be coupled to one of the multipolar connectors; moreover,the master unit comprises the output interface toward the control unit.

The processing and transmission system also comprises one or more slaveunits which are connected to the master unit. Each slave unit has atleast one external port, defining one of the input channels of thesystem for a connection to a device. Moreover, the slave unit has itsown memory and a secondary processor. The slave unit is also equippedwith a first socket and a second socket, configured to be coupled atleast to a first and a second connector of the multipolar connectors. Inthis way, the slave unit is interconnected with the master unit.

The multipolar cable makes it possible to connect a plurality of slaveunits to each other and to the master unit, for example in a daisy chainconfiguration, in such a way that there is a single multipolar cable inthe data processing and transmission system connected to the master unitto exchange data with the slave units.

The data processing and transmission system according to the inventionmakes it possible to create a network including a master unit and one ormore slave units, interconnected by means of the multipolar cable.

It is possible to position the slave units in the proximity of therespective devices, reducing the noise and the number of connectioncables.

This contributes towards increasing the accuracy of the data processingand transmission system. Moreover, the system is particularly flexible,because it may be adapted to interconnect different configurations ofdevices simply by adding or removing slave units, without having toover-size the master unit.

In order to simplify the assembling of the system and increase themodularity, for each slave unit the first and/or the second socket maybe connected to at least one first or one second socket of a furtherslave unit either directly or by a piece of the multipolar cable. Inthat way, it is possible to make a modular structure, having at least afirst and a second slave unit, in which one of the first and secondslave units has the first socket coupled to one of the connectors of themultipolar cable and the second socket connected, directly or by a pieceof cable, to the first socket of the other slave unit.

The multipolar cable defines a plurality of communication channels,which are different from each other according to hierarchical levelsdepending on the communication speed and complexity (for example,Ethernet, CAN and RS485, in decreasing order of ranking).

Moreover, the slave unit always has its own unique address which may bedetected by the master unit through the multipolar cable and acts as arepeater of the signals circulating in the multipolar cable.

The slave units may have different functions (depending on theconfiguration of one of their printed circuit board), but they have incommon the presence of an external port for connection to a device, amemory and a processor adapted to allow a communication through thechannel of higher ranking (within the plurality of channels provided bythe multipolar cable).

The system can also comprise at least one ancillary unit, provided witha first socket and a second socket configured to connect to at least oneof the first and second sockets of at least one slave unit.

The ancillary unit is interconnected in the multipolar cable and itpropagates the signal.

The ancillary unit, relative to the slave unit, does not have one ormore of the above-mentioned features: external port, memory or processoradapted to allow a communication through the channel of higher ranking.The ancillary unit differs from the slave unit since it may have one ormore of these properties, but not all. For example, an ancillary unitmight be without the memory and/or the external port and/or a processor;it could have a programmable logic or other processing means allowingaccess to a communication channel of lower ranking (for example, CAN andRS485); or, it could be totally invisible to the master unit (as it doesnot have an identification code), in which case it can communicateexclusively with the slave unit to which it is connected.

In an embodiment, at least one operation of the ancillary unit isexclusively related to an operation of the slave unit to which it isconnected. In other words, in relation to this operation, the ancillaryunit performs only functions necessary for the respective slave unit.

According to another aspect of the modularity of the system, the masterunit is connected to other units, which allow an extension of thefunctions of the master unit.

To connect the master unit quickly and easily to another unit, that isto say, a supplementary unit (positioned in the same panel and alongsidethe master unit), the master unit is equipped with a first and a secondsocket and the system comprises a dedicated bridge connector. The bridgeconnector has a first and a second end and comprises a first multipolarconnector at the first end and a second multipolar connector at thesecond end. Both the first and the second connector can be coupled(directly) to one of the first or second sockets of the master unit andto a socket of the supplementary unit.

It should be noted that the bridge connector according to the presentinvention can be used, advantageously, in any data processing andtransmission system for numeral control unit adapted to control amachine tool, which comprises a unit adapted to be connectable modularlyto another unit positioned alongside (for example with both the unitsconnected mechanically to a DIN rail in an electrical panel orswitchboard).

More generally, the connector bridge according to the present inventionmay be used in measuring and/or control systems comprising at least onefirst and one second unit positioned side by side and configured to beconnected to each other.

Preferably, in the bridge connector according to the present invention,both the first and the second connector of the bridge connector hasretractable (spring type) electrical contacts to facilitate theoperations of electrical connection to corresponding sockets ofrespective units of the system, these sockets comprising, for example,planar electrical contacts, or padtime slot s, adapted to cooperate withsuch retractable contacts.

Furthermore, with regard to the simplicity of installation and wiring,according to another aspect of the invention, the data processing andtransmission system comprises a fast wiring multipolar connector, forassembling in-situ, quickly and simply the connector to an end of themultipolar cable.

The fast wiring multipolar connector is equipped with perforatingelectrical contacts, configured to perforate an insulating sheath whichcovers the wires contained in the multipolar cable and fixed to thewires.

Moreover, the fast wiring multipolar connector has a first body,equipped with a first group of electrical contacts with a plurality ofcontact pins which can be coupled to the multipolar socket of the masterunit, and a second body, which can be plugged into the first body andequipped with perforating electrical contacts. The contact pins of thefirst body are retractable (or “spring type”) electrical contacts.

It should be noted that the fast wiring multipolar connector accordingto the present invention can be used, advantageously, in any dataprocessing and transmission system for numeral control unit adapted tocontrol a machine tool, which uses a multipolar cable. For example, itshould be noted that the advantage of assembling in a quick and easymanner a connector to one of the two ends of the cable (the one to beconnected to the unit positioned in the electrical cabinet) is notlimited to distributed intelligence systems.

On the other hand, the other end of the multipolar cable preferably hasa pre-assembled multipolar connector, having special sealing capacitywith regard to moisture and dust.

This makes it possible to use the pre-assembled multipolar connector inthe polluted environment and use the free end of the multipolar cable toconveniently perform passages in machine cable carrying ducts, and then,after suitably arranging the multipolar cable, assembling the fastwiring multipolar connector to the free end of the multipolar cable andconnecting it to the master unit in the clean environment.

More generally speaking, the fast wiring multipolar connector accordingto the present invention may be advantageously used in measurementand/or checking systems comprising at least one first and one secondunit with sockets configured to be coupled to multipolar connectors of acable, to make the electrical connection.

According to another aspect, the multipolar cable also has the functionof electrically powering the slave units.

This reduces further the installation and maintenance time, andsimplifies installation. Moreover, the presence of a single multipolarcable simplifies the sizing of the network defined by the system.

According to another aspect, the master unit has a clock and each slaveunit has its own clock. The main processor is programmed to generate asynchronisation signal and to transmit the synchronisation signalthrough the multipolar cable, in order to synchronise all the clocks ofthe slave units with the clock of the master unit.

In a preferred embodiment, the synchronization of the clocks isimplemented according to the method provided by the IEEE 1588 PrecisionTime Protocol (PTP). The master unit sends, through for example theEthernet communication channel, a synchronization signal that isreceived almost simultaneously by all the slave units. Morespecifically, the synchronization signal sent by the master unit ispropagated through the slave units, starting from the nearest one in theseries, and is received by every slave unit that synchronizes its ownclocks independently from the other slave units. Every slave unitreceives the synchronization signal with a minimal delay with respect tothe upstream slave unit due to the signal propagation time. Thesynchronization signal is transmitted as it is by every slave unit, thatis to say, every slave unit receives the synchronization signal as it isgenerated by the master unit, the signal is not processed by the slaveunit before reaching the other one. This allows the data processing andtransmission system to correlate and synchronise the data in aparticularly simple and effective manner.

More specifically, two or more slave units comprise an electroniccircuit for generating an alternating electric excitation signal (for aninductive transducer of a sensor to which the slave unit is connected).All the alternating electric excitation signals generated aresynchronised temporally with each other. This prevents noise in thesystem due to a beat phenomenon generated by the simultaneous presenceof unsynchronised sinusoidal signals. This noise is typically lowfrequency and is particularly harmful to the system.

According to another aspect, relative to the mode of transferring datafrom the slave units to the master unit, the main processor isprogrammed to divide a data transmission time interval into a pluralityof time slot sand to uniquely assign to each slave unit a correspondingtime-slot of the plurality of time slots. For each slave unit, thesecondary processor can be set for transmitting data through themultipolar cable only within the respective time slot.

This makes it possible to transmit data from the slave units to themaster unit with maximum latency time, contributing towards aparticularly reliable in-process checking, which requires responseswithin a quick and clear time frame.

Preferably, the main processor is programmed to assign to each slaveunit a unique identification code and it is programmed to perform acontinuous data collection cycle. At each time slot of the datatransmission time interval the main processor receives and stores thedata transmitted by the corresponding slave unit and associates the datawith the slave unit which the data comes from.

It should be noted that each slave unit is configured to receive atleast one operational signal through the external port, and to acquireand store corresponding data.

According to another aspect of the data processing and transmissionsystem according to the present invention, each slave unit is configuredto assign corresponding acquisition instants to the data acquired, onthe basis of its own clock.

This favours the capacity of the system to keep under control a largenumber of process parameters, in order to improve the quality standardsand guarantee greater reliability of operation of the machine.

It should be noted that, in the data processing and transmission systemaccording to the present invention, according to another aspect, themaster unit comprises a diagnostic block.

The diagnostic block has electronic circuits and is configured fordetecting or collecting, at least for the master unit, at least onepower supply parameter. Alternatively or in addition, the diagnosticblock is configured for collecting, at least for the master unit and/orfor one or more of the slave units, an internal temperature.

Preferably, the diagnostic block is configured for collecting theinternal temperatures of both the master unit and all the slave (andancillary) units.

In an embodiment, the diagnostic block is configured for collecting atleast one power supply parameter also for the slave units, takenindividually, or for the entire system, that is, all the slave units andthe master unit.

For example, the diagnostic block of the master unit is configured fordetecting or collecting one or more of the following parameters: supplyvoltage, electrical current draw, power draw.

Preferably, the diagnostic block is connected to an electrical powersupply of the master unit: to prevent that the detection of the at leastone power supply parameter causes an electromagnetic pollution in theelectronic components of the system the diagnostic block is coupled tothe main processor through an opto-isolated interface.

It should be noted that the multipolar cable preferably contains one ormore wires (at least one supply and one return) which define anelectrical power supply for the system, in particular for the slave andancillary units.

Preferably, the slave (and ancillary) units and preferably also themaster unit are connected in parallel to the power supply wires.

Preferably, the slave (and ancillary) units and preferably also themaster unit, each have a power supply circuit (for example a DC/DCconverter) defining a galvanic insulation, interposed between therelative electronic components (to be powered) and the power supplywires. The purpose of this is to guarantee that the electroniccomponents of the slave (and ancillary) units and the master unitoperate in a “clean” electric room.

Preferably, the diagnostic block has its own connection with the powersupply wires, whilst the interface with the main processor is insulatedgalvanically, for example by an optical connection (coupling). Thisallows the diagnostic block to read voltage and current or otherquantities representing an electricity consumption by the system,without causing alterations in the electrical power supply of theelectronic components of the master unit. An optical coupling withrelative voltage or current reading may be provided in one or more ofthe ancillary units.

This makes the data processing and transmission system particularlyreliable, allowing the energy consumption to be monitored andidentifying any faults, with the possibility of generating warning orfault signals and preventing these situations.

This and other features of the invention will become more apparent fromthe following description of a preferred embodiment, illustrated by wayof non-limiting example in the accompanying drawings, in which:

FIG. 1 schematically shows a front view of a numerical control machinetool;

FIG. 1A schematically shows the inside of the machine tool of FIG. 1,containing a system according to the present invention;

FIG. 1B shows a diagram representing the system according to the presentinvention;

FIG. 2 shows a perspective view of the master unit belonging to thesystem of FIG. 1, which can be connected to a supplementary unit bymeans of a bridge connector according to the present invention;

FIG. 3 shows a perspective view of a slave unit belonging to the systemof FIG. 1;

FIG. 4A shows a perspective view of a group comprising the slave unit ofFIG. 3 connected to an ancillary unit, according to the presentinvention;

FIG. 4B shows an exploded view of the group of FIG. 4A;

FIG. 5 shows a side view of a cross section of the slave unit of FIG. 3,with certain details omitted;

FIG. 6 shows an exploded perspective view of a fast wiring multipolarconnector belonging to the system of FIG. 1, with certain detailsomitted;

FIG. 6A shows an enlarged cross sectional detail of the fast wiringmultipolar connector of FIG. 6;

FIG. 7 shows a cross section of a bridge connector, which connects amaster unit and a supplementary unit according to the present invention.

With reference to the attached drawings, the reference number 1indicates a data processing and transmission system for a numericalcontrol unit 2 adapted to control a machine tool 3.

The machine tool 3 has a work chamber 3A, in which at least one tool ispositioned. The work chamber 3A defines its own inner space 3C, that isto say a work space. Typically, the work space 3C constitutes a polluted(dirty) environment.

The machine tool 3 also comprises, typically, an electrical panel orswitchboard 3B, in which the numerical control unit 2 is positioned. Theelectrical panel 3B defines its own inner space 3D. The inner space 3Dof the electrical panel 3B constitutes a relatively clean environment;indeed, it is separated, for example by a wall, from the work space 3Cof the machine tool 3.

The system 1 comprises at least one input channel 4 adapted to a transitof operational signals from devices 15 present in the machine tool 3 orto devices 15 present in the machine tool 3. The system 1 also compriseselectronic circuits configured to process the operational signals tomake available on an output interface 5 control signals for thenumerical control unit 2.

Typically, the devices 15 are positioned in the work space 3C of themachine tool 3 and can be for example sensors or actuators.

The system 1 according to the invention comprises one or more slaveunits 6, that is, at least one slave unit 6, provided with at least oneexternal port 6A, defining the input channel 4.

The system 1 comprises a master unit 7 having the output interface 5.

Preferably, the master unit 7 is located in the space 3D of theelectrical panel, and is therefore positioned in the non-pollutedenvironment, close to the numeral control unit 2.

On the other hand, preferably, at least one of the slave units 6 islocated in the work space 3C, close to a respective device 15 (thusminimising also the length of the cable, or the cables connecting theslave unit 6 to the respective device 15). Generally speaking, slaveunits 6 are preferably located in the work space 3C; however, one ormore slave units 6 may be positioned in the space 3D of the electricalpanel, depending on the relative function.

The master unit 7 comprises a memory (that is, main memory) 7R and amain processor 7S. Each slave unit 6 comprises a memory (that is,secondary memory) 6R and a secondary processor 6S. Preferably, the slaveunit 6 is configured for acquiring at least one operational signalthrough the external port 6A and storing it in the memory 6R.

The system 1 comprises a multipolar cable 8 for connecting at least oneof the slave units 6 to the master unit 7. Preferably, the multipolarcable 8 is inserted in an opening in the partition wall which separatesthe work space 3C from the space 3D of the electrical panel.

The connection between the slave units 6 may be carried out by pieces ofmultipolar cable 8 or by direct connection of the sockets 6B and 6C.

In an embodiment, the multipolar cable 8 has a first and a second end,each end provided with a multipolar connector 9. The master unit 7comprises at least one first socket 7A configured to be coupled to oneof the multipolar connectors 9. Each slave units 6 is provided with afirst socket 6B and a second socket 6C, configured to be coupled atleast to one first or one second connector of the multipolar connectors.The multipolar cable 8 connects the at least one slave unit 6 to themaster unit 7.

In an embodiment, the system 1 comprises a plurality of slave units 6connected in series to each other and one of them is connected to themaster unit 7 by means of a piece of the multipolar cable 8. The slaveunits are connected to each other directly or by the multipolar cable 8.

In an embodiment, the system 1 comprises at least two slave units 6,that is to say, it comprises a plurality of slave units 6.

In an embodiment, the system 1 comprises a multipolar connector 16. Themultiple connector 16 has a first, a second and a third multipolarconnector 9, each of which is configured to couple to one of themultipolar connectors of the multipolar cable 8 and connect to the firstor the second socket of the slave units 6. It should be noted that inthis way it is possible to make branches, for example connecting thefirst multipolar connector to a first slave unit 6, the secondmultipolar connector to a second slave unit 6 and the third multipolarconnector, either directly or indirectly, to the multipolar cable 8which is connected to the master unit 7.

The multiple connector 16 has its own processor, programmed to detectthe data entering in one of the three multipolar connectors and tohandle a flow of data coming from the remaining two multipolarconnectors.

The present invention also relates to a fast wiring multipolar connector12. The purpose of the fast wiring multipolar connector 12 is to allow amultipolar cable to be connected, that is, provided with a connector atone end, in a fast and simple manner, on-site, without the need forspecific or complicated tools (for example, a screwdriver and a pair ofscissors are sufficient).

In an embodiment, the system 1 comprises the fast wiring multipolarconnector 12, which can be coupled to an end of the multipolar cable 8.

The fast wiring multipolar connector 12 of the illustrated example isequipped with a plurality of perforating electrical contacts 12P,configured to perforate an insulating sheath which covers wires 8Ahoused in the multipolar cable 8 and fasten and electrically connect thewires and the perforating electrical contacts to each other. Accordingto an embodiment, the perforating electrical contacts 12P are housed ina plurality of seats 12S of a frame which also house the sheathed wires8A of the multipolar cable 8. A plurality of movable elements 12D,coupled to the frame, are adapted for cooperating, in the seats, withthe wires housed in the multipolar cable to fasten and the electricallyconnecting the wires and the perforating electrical contacts to eachother.

In an embodiment, the movable elements 12D are covering elements, eachof which is movable between a first position, wherein it closes therespective seat and presses on the wire 8A positioned in this seat, andan open position, which allows the insertion and extraction of the wire8A in and from the seat.

The perforating electrical contacts 12P may have an elongate shape andcomprise one or more conductive teeth (that is, plates or other cuttingelements made of a conductive material) at one end, whilst the free endopposite may have the form of gripper, as shown in FIG. 6A. When thewire 8A is positioned in the seat 12S and the covering element 12D isclosed, the conductive teeth of the respective perforating electricalcontact perforate the sheath thus connecting electrically the wire andthe perforating electrical contact.

This is the preferred embodiment, but the perforating contacts may bepositioned, for example, in the covering element 12D and be movable withit.

In a preferred embodiment, the fast wiring multipolar connector 12 has afirst body 12A and a second body 12B.

In an embodiment, the first body 12A has a support with two oppositefaces which may comprise at least one printed circuit board, or two ormore printed circuit board rigidly and electrically connected to eachother. Front electrical contacts of a first group of electricalcontacts, or contact pins 12C, are fixed to one of the faces of thesupport and can be coupled to corresponding electrical contacts (forexample pads, that is to say planar electrical contacts, or holes) of amultipolar socket (for example a socket 7A of the master unit 7 or asocket 6B, 6C of a slave unit 6).

In an embodiment, the contact pins 12C are retractable, or “springtype”, that is to say, they are movable elastically independently ofeach other.

Electrical contacts of a second group of electrical contacts are fixedto the other face of the support of the first body 12A. The second body12B can be plugged into the first body 12A. In an embodiment, theelectrical contacts of the second group, electrically connected to thecontact pins, are housed in hollow coupling elements 12E fixed to therespective face of the support.

The second body 12B has a first and a second end, the latter connectedto the cable 8.

At the first end of the second body 12B there are the ends in the formof a gripper of the perforating electrical contacts 12P which, in anembodiment, are housed in protruding coupling elements 12F fixed to theframe. More specifically, the protruding coupling elements 12F can besnap coupled to the hollow coupling elements 12E to plug the second bodyinto the first one and electrically connecting the perforatingelectrical contacts and the electrical contacts of the first group.

FIG. 6 shows only one half of a protective casing, of known type, forthe fast wiring connector.

In an embodiment, the master unit 7 has a clock and each slave unit 6has its own clock. The main processor 7S of the master unit 7 isprogrammed to generate a synchronisation signal and to transmit thesynchronisation signal through the multipolar cable 8, synchronising theclocks of the slave units 6 with the clock of the master unit 7.Preferably, each slave unit 6 has its own unique address which may bedetected by the master unit 7 through the multipolar cable 8.

With regard to the slave unit 6 (or slave units 6), the following shouldbe considered.

In an embodiment, the slave unit 6 comprises a first electronic boprinted circuit board and 6D connected to the first socket 6B and to thesecond socket 6C and configured for managing data transmission throughthe multipolar cable 8. The first printed circuit board 6D comprises aprocessor (for example a CPU).

The slave unit 6 comprises a second printed circuit board 6E connectedto the first printed circuit board 6D and to the external port 6A andadapted for managing the transit of operational signals through thecorresponding input channel 4.

In an embodiment, the second printed circuit board 6E comprises afurther, relative processor; alternatively, the second printed circuitboard 6E my use the processor of the first printed circuit board 6D (andis free of its own processor).

Preferably, the first printed circuit board 6D is the same for all theslave units 6, both in terms of software and hardware.

On the other hand, the second electronic board 6E preferably has aconfiguration (hardware and/or software) which depends on the functionperformed by the slave unit in which it is mounted.

This simplifies the production of the system and reduces the storagerequirements.

In an embodiment, the slave unit 6 comprises a protective shell 6F,containing the memory 6R, the secondary processor 6S, the first printedcircuit board 6D and the second printed circuit board 6E. Preferably theprotective shell 6F defines a seal equal to or greater than IP65rating.

In a preferred embodiment, the protective shell 6F comprises a firstside wall 6G on which is positioned the first socket 6B and a secondside wall 6H on which is positioned the second socket 6C. The protectiveshell 6F also comprises an upper wall 6I on which is positioned at leastone external port 6A.

In an embodiment, the external port 6A of the slave unit 6 is enabledboth for transmitting and receiving operational signals. The slave unit6 is connectable, by means of the external port 6A, to one or moresensors 15 present in the work space 3C of the machine tool 3. The term“sensor” identifies for example a measurement head with a positiontransducer, a vibrations sensor or an acoustic sensor. These sensors areadapted to generate signals representing parameters relative to themachining performed by the machine tool 3, detected during the operationof the machine 3. The slave unit 6 is connectable to the sensors 15 foracquiring these signals. The slave unit 6 is also connectable toactuators adapted to receive control signals transmitted by the slaveunit 6.

In a system 1 with two or more slave units 6 connected to sensors withinductive measurement transducers, the slave units 6 comprise anelectronic circuit for generating an alternating electric excitationsignal, and all the alternating electric excitation signals aresynchronised in time with each other. Each of the two or more slaveunits 6 is programmed to transmit as output the alternating electricexcitation signal through the respective external port 6A, in order toenergise the corresponding measuring transducer made with a variableinductive coupling.

In an embodiment, each of the two or more slave units 6 comprises agenerator of a first and a second digital PWM (pulse width modulation)signal. Each of these two or more slave units 6 comprises processingcircuits adapted to receive the first and second digital PWM signals andto process them to generate the alternating electric excitation signalconsisting of a sinusoid.

In an embodiment, the generation of the sinusoid for exciting thetransducer is achieved with a digital technique, according to which twoPWM digital signals are generated. The PWM signals are summed and/orsubtracted, or in any case combined according to a mathematicalfunction; the signal resulting from that sum or subtraction orcombination is filtered to generate the sinusoid.

This technique make it possible to obtain a sinusoid with a very lowlevel of harmonic distortion, thanks to the possibility of convenientlymodulating the duration of the two PWM digital signals. It should alsobe noted that the use of a digital device facilitates thesynchronisation of the generation of the sinusoid with signals comingfrom the outside.

In an embodiment, for each of the two or more slave units 6, theelectronic circuits for generating the alternating electric excitationsignal are configured to correct the alternating electric excitationsignal in phase, preferably at predetermined regular time intervals, inorder to synchronise it in phase with another alternating electricexcitation signal generated by another slave unit 6.

In an embodiment, each slave unit 6 has a timer to generate a referencesignal (for example a square wave), which is used to generate thesinusoid (for example using one or more PWM signals). Thanks to the factthat each slave unit 6 has a clock (connected to the timer) and all theclocks are synchronised, the slave unit 6 is programmed to vary overtime the frequency of the reference signal, to phase all the referencesignals of all the slave units 6 (all those designed to generatereference signals), since they are synchronised with a reference signalgenerated by the master unit or with the reference signal generated byone of the slave units (selected in an arbitrary way as a reference forthe others). As a result, the sinusoids generated by all the slave unitsare synchronised with each other.

In an embodiment, each slave unit 6 is configured for acquiring, throughthe external port 6A, at least one operational signal. The operationalsignal may be a digital signal comprising data, or an analogue signalrepresenting the trend of quantity and therefore having an informationcontent.

Preferably, each slave unit 6 is configured to store the operationalsignal and is programmed to assign to the data acquired through theexternal port 6A corresponding acquisition instants, on the basis of arelative clock.

The data acquired by the devices 15 are stored in the slave units 6 andtransmitted according to a communication protocol to the master unit 7.

A corresponding timing information detected by the high precision clockpresent in each slave unit is associated to the data acquired. Thetiming information is sent to the master unit 7 associated with the dataacquired.

This allows (in combination with the fact that the clocks of the slaveunits 6 are synchronised with that of the master unit) the master unit 7to collect data coming from different slave units 6 and to correlatethem in time with each other, either in real time (this is particularlyuseful for the in-process checking) or a posteriori.

In an embodiment, each slave unit on 6 is programmed for storing, for apredetermined interval of time, the data acquired through the externalport 6A. Preferably, each slave unit 6 is programmed for storing thedata in a data packet and is programmed to transmit at least the datapacket to the master unit 7, through the multipolar cable 8.

In an embodiment, the slave units 6 of the plurality of slave units 6can be connected together to form a modular structure.

Preferably, the first socket 6 of the slave unit 6B is male and thesecond socket 6C is female. For example, the first socket 6B of a firstslave unit can be coupled to a second socket 6C of a second slave unit;the second socket 6C of a first slave unit can be coupled to a firstsocket 6B of a second slave unit. In an embodiment, the first slave unithas the first socket 6B coupled to one of the multipolar connectors 9 ofthe multipolar cable 8 and the second socket 6C connected, for exampledirectly coupled, to the first socket 6B of the second slave unit; thesecond socket 6C of the second slave unit is coupled to one of themultipolar connectors 9 of the multipolar cable 8.

If the slave units 6 are not connected with each other by coupling therespective sockets 6B, 6C, they may be connected using the multipolarcable 8. For example, the multipolar cable 8 comprises two or morepieces, each having a first and a second end equipped with a multipolarconnector 9, to connect to each other the slave units 6 and/or toconnect at least one slave unit 6 with the master unit 7.

It should be noted that the term “slave unit” identifies a unit whichinterfaces a device, such as a sensor, with a network comprising atleast one slave unit and the master unit 7 connected by the multipolarcable 8. Preferably, the slave unit is able to perform basic processingsuch as filtering and/or conditioning a signal or even more complexoperations. For example, the slave unit 6 is able to autonomouslyprocess control signals for an actuator connected to it, even as afunction of a signal detected by a sensor connected to the slave unit.

In an embodiment, the system 1 may comprise at least one ancillary unit10, provided with a first socket 10A and a second socket 10B. The firstsocket 10A and the second socket 10B of the ancillary unit 10 areconfigured to connect at least to one of the first socket 6B and secondsocket 6C of the slave unit 6.

The ancillary unit 10 differs from the slave unit 6 due to the fact thatit has a reduced processing and/or communication capacity.

It should be noted that the slave unit 6 has, as well as a memory, aprocessor which allows to perform complex processing and exchange datathrough a complex and fast communication channel (for example Ethernet).

Unlike the slave unit 6, the ancillary unit 10 does not have aprocessor, that is, a data processing system; alternatively, theancillary unit 10 can have its own processing means, consisting forexample of a programmable logic.

In predetermined cases, the ancillary unit 10 is equipped with its ownmemory.

The ancillary unit 10 may not have access to any communication channeldefined by the multipolar cable 8, or may be configured for exchangingdata through a communication channel defined by the multipolar cable 8,preferably of lower ranking than the communication channel used by theslave units (for example, a CAN or RS485 communication channel).

In an embodiment, at least one operation of the ancillary unit 10 iscontrolled by an operation of the slave unit to which it is connected.

For example, if the slave unit 6 is connected to a device comprising ameasurement head with a measuring feeler, a relative ancillary unit 10may comprise a solenoid valve and a connecting element 10C for acompressed air circuit, to retract the measuring feeler in a per seknown step of a checking cycle.

In another example, it should be noted that the multiple multipolarconnector 16, which does not have an external port for connection to adevice 15, itself defines an ancillary unit 10.

In another example, the ancillary unit 10 might consist of a voltageamplifier, connectable to an external electrical power source, toprovide an output supply voltage higher than the input voltage. Thistype of ancillary unit 10 does not have a memory and processor.

With regard to the master unit 7, the following should be considered.

In an embodiment, the master unit 7 comprises a first socket 7A and asecond socket 7B. For example, each of the sockets may comprise planarelectrical contacts or “pads” which can be coupled to respectiveretractable electrical contacts present in multipolar connectors.

In an embodiment, the master unit 7 has the shape generically of aparallelepiped with a front wall 7C, a back wall 7F and a bottom wall7T. Preferably, the first socket 7A and the second socket 7B arepositioned in the front wall 7C of the master unit 7. In an embodiment,the master unit 7 comprises elastic snap-on locking elements (not shown,per se known and located on the back wall 7F) which are configured tofix the master unit 7 to a supporting or mounting bar of the electricalpanel, for example a DIN rail.

Preferably, the first socket 7A and the second socket 7B of the masterunit 7 are positioned on opposite sides of the front wall 7C,respectively close to a first outer side wall 7D and a second outer sidewall 7E of the master unit 7. Preferably, the first socket 7A and thesecond socket 7B of the master unit 7 are positioned at the same height,that is to say, at a same distance from the bottom wall 7T of the masterunit 7.

According to a preferred embodiment, the master unit 7 has flat sidewalls 7D, 7E and a plurality of fins 17 which protrude from the sidewalls 7D, 7E. The function of the fins 17 is to favour heat exchange andthus the cooling of the master unit 7. Preferably, the fins 17 areparallel to each other and perpendicular to the bottom wall 7T of themaster unit 7. Preferably, when the master unit 7 is fastened to thesupport (for example to the DIN rail), the fins are oriented vertically.

More specifically, the fins 17 are arranged perpendicularly to thelocking elements of the master unit 7 to a support. For example, thefins are oriented perpendicularly to the locking elements on the backwall 7F for connection to the DIN rail.

Moreover, the top surface of the master unit 7 is also provided withfins.

Preferably, the master unit 7 also comprises a cooling fan (notillustrated) positioned in a space inside the master unit 7. The purposeof the cooling fan is to make uniform the temperature inside the masterunit 7 and it cooperates with the fins 17 to cool the electroniccomponents housed in the master unit 7.

In a preferred embodiment the master unit 7 comprises a power supplysocket 7G, a network socket 7H, a field bus socket 7I adapted to coupleto a further multipolar signal connector, one or more alarm warninglights 7L, a peripheral port 7M for a connection to a display which isremote or can be made remote.

The master unit can also comprise one or more USB 7N and/or USBOn-The-Go 7P ports (also known as USB OTG) and/or a HDMI 7Q port.

In a preferred embodiment, the electricity supply socket 7G, the networksocket 7H, the field bus socket 7I, the alarm warning lights 7L, theperipheral port 7M, the USB ports 7N, 7P and the HDMI port 7Q arepositioned on the front wall 7C of the master unit 7.

In an embodiment, the main processor 7S is programmed to divide a datatransmission time interval into a plurality of time slots and touniquely assign to each slave unit 6 a corresponding time slot of theplurality of time slots. Preferably, for each slave unit 6, thesecondary processor 6S can be set for transmitting data through themultipolar cable 8 only within the respective time slot.

This makes a particularly effective data transmission possible betweenthe slave units 6 and the master unit 7, which guarantees a responsewithin a clear time frame. This is particularly advantageous in order todeal with the need to transfer data in real time in in-process checkingsystems. Moreover, unlike prior art systems wherein the master unitinterrogates the slave unit each time (using the “polling” technique),this solution allows a drastic reduction in the time necessary for themaster unit 7 to collect data stored by the slave units 6, because thelatter do not wait to be interrogated by the master unit 7 (thisinterrogation occupies band width and slows down the communication), buttransmits autonomously within its own time slot.

In a further example embodiment, the main processor 7S is programmed toassign to each slave unit 6 a unique identification code and it isprogrammed to perform a continuous data collection cycle. The mainprocessor 7S, in every data transmission time interval, is configured toreceive and store the data transmitted from the corresponding slave unit6. The main processor 7S is also configured for associating the datawith the slave unit 6 which they come from.

As regards a step of configuring the system wherein the master unitassigns identification codes, attention is drawn to the following.

In an embodiment, each slave unit 6 (and, if necessary, the ancillaryunits 10 equipped with processing means) has a first and a secondswitch; the first switch is positioned between the first socket 6B andthe processor, the second switch is positioned between the second socket6C and the processor. The first and second switches could beconventional electrical switches, but preferably they are electronicswitches that are made by means of appropriate circuits and can beactuated via software (for example from the sockets 6B, 6C).

At the start of the step of configuring the system 1, for each slaveunit 6 (and for the ancillary units 10 equipped with processing means),the first switch is set in the closed position and the second switch isset up in the open position.

In the case of the multiple connector 16, it has a first, a second and athird switch; in this case the first switch is set in the closedposition and the second and the third switches are set in the openposition.

It is important to carefully position the first switches always facingtowards the master unit 7; consequently, the second switches arepositioned facing away from the master unit 7.

After the step of arranging the network of the system 1, comprising theslave units 6 (and the ancillary units 10), which are connected inseries to the master unit 7 in a chain configuration, in particular ofthe ‘daisy chain’ type, the step of configuring the system is started,for example by means of the procedure which follows.

The master unit 7 sends a (first) signal, through the multipolar cable8, towards the first slave unit 6 of the chain defined by the system 1;the signal constitutes an interrogation and is received by the processorof the (first) slave unit 6 through the corresponding first switch (thesignal does not continue further because the second switch of the firstslave unit 6 is open). The processor replies to the interrogation(because the slave unit 6 is programmed to provide the response to theinterrogation) by providing details regarding its existence and thefunction of the slave unit 6. The master unit 7 receives the response,records it and stores the position and the function of the slave unit 6and assigns to the slave unit 6 a unique identification code. Moreover,the slave unit 7 transmits a control signal to the processor of the(first) slave unit 6, for switching the second switch from the openposition to the closed position.

Subsequently, the master unit 7 sends a (second) signal through themultipolar cable 8, which, like the first one, constitutes aninterrogation for a processor. The signal is received by the processorof the second slave unit 6 (the first slave unit downstream with respectto the first slave unit 6) through the corresponding first switch (thesignal does not continue further because the second switch of the secondslave unit 6 is open).

The operation is thus iteratively repeated for all the other slave units6 until a unique identification code has been assigned to each slaveunit.

According to an alternative embodiment, it is sufficient for the slaveunit 6 to comprise at least one switch, in particular the second switchpositioned facing away from the master unit 7. Indeed, in an embodimentof the invention, the first switch mentioned above may remain closed andbe replaced by a permanent electrical connection.

In a further embodiment, the main processor 7S is programmed to dividethe data transmission time interval into a number of time slots greaterthan the number of slave units 6 of the system 1, saving at least oneadditional or extra time slot (in addition to the time slotscorresponding to respective slave units 6 and uniquely assigned tothem). Preferably, in the additional time slot of the continuous datacollection cycle, the main processor 7S is programmed to set parametersof the slave units 6 through the multipolar cable 8. For example, themain processor 7S is programmed to re-set valid parameters for the slaveunits 6, such as, for example, the duration of the data transmissiontime interval, and/or to perform the downloading of a digital documentin the processor of the slave unit 6. The additional time interval canalso be exploited by using, for example, a file transfer protocol suchas FTP.

In an embodiment, the master unit 7 comprises a diagnostic block havingelectronic circuits. The diagnostic block is configured for detecting orcollecting, for the slave units 6 and/or for the master unit 7, at leastone power supply parameter, representing a supply voltage. Thediagnostic block is configured for collecting, in addition oralternatively to the power supply parameter, for each slave unit 6and/or for the master unit 7, an internal temperature.

A temperature sensor may be present in each slave unit 6 and/or in themaster unit 7 for providing a value relative to the internaltemperature.

In an embodiment, the diagnostic block of the master unit 7 isconfigured to collect, for the slave units 6 and/or for the master unit7, one or more of the following parameters: power supply voltage,electrical current draw, power draw.

In other words, the diagnostic block can detect or collect at least onepower supply parameter relative to the entire system (that is, the slaveunits 6 and the master unit), only to the master unit 7 or to each slaveunit 6. The diagnostic block is also able to collect, alternatively orin addition to the power supply parameter, a temperature inside thesingle slave unit 6 and/or the master unit 7.

Preferably, the diagnostic block of the master unit 7 is programmed forstoring data representing a trend over time of the power supplyparameter and/or the internal temperature detected.

In an embodiment, the diagnostic block of the master unit 7 has storedin its memory one or more reference values of the power supply parameterand/or internal temperature. The diagnostic block is programmed tocompare values, preferably detected in real time, of the power supplyparameter and/or internal temperature with the reference values. Thediagnostic block is preferably programmed to generate an alarm dependingon the comparison carried out. For example, the diagnostic block isprogrammed to generate an alarm if the internal temperature exceeds areference value for a predetermined time. In an embodiment, thediagnostic block is programmed to generate an alarm if the power supplyparameter differs from a reference value for a predetermined time.

In an embodiment, the slave unit 6 is programmed to transmit insynchrony to the master unit 7 data relating to the operational signalsand data relating to the at least one power supply parameter and/orinternal temperature.

The master unit 7 is configured to perform the most complex mathematicaloperations requested by the various measuring cycles and it has the dutyof interpreting and/or combining the information received from thevarious sensors (by means of the slave units 6), translating them intosignals that can be received and processed by the numerical control unit2 and, generally speaking, it is the only interlocutor (within thesystem 1) of the numerical control unit 2.

In an embodiment, the system 1 comprises a connector bridge 11 having afirst and a second end. The bridge connector 11 comprises a firstconnector 11A at the first end and a second connector 11B at the secondend. Each of the first and second connectors 11A, 11B compriseselectrical contacts and can be coupled to the first or to the secondsocket of the master unit 7.

In an embodiment, the connector bridge 11 comprises asymmetricallyshaped profiles (which define mechanical keys) and the sockets 7A, 7Bwith which the connector bridge 11 is designed to be coupled havecorresponding shaped profiles adapetd to cooperate with the shapedprofiles of the connector bridge 11 to facilitate the correctpositioning of the connector bridge in a step of alignment of theseshaped profiles.

In an embodiment, the connector bridge 11 comprises a rim made ofinsulating material (that is, made of electrical or dielectricinsulating material), with a central opening and an edge which can bepositioned around the electrical contacts of the first or secondconnector 11A, 11B. The function of the insulating rim is to preventaccidental short circuits during positioning of the connector bridge 11.

In the system 1, the connector bridge 11 has mainly the function ofconnecting a first and a second unit, in particular the master unit 7 toat least one other unit which defines a supplementary unit 13 equippedwith a front wall with at least one socket.

Preferably, the first and second connector 11A, 11B have springcontacts, that is to say, retractable contacts, adapted to touch planarelectrical contacts or “pads” of the respective sockets. This makes itpossible to annul mechanical clearances and compensate for positioningerrors between the units to be connected together.

Preferably, the edge delimiting an area occupied by the spring contactsis raised; this is to protect the contacts in the case of accidentalimpact.

Moreover, according to the preferred embodiment, the first and secondconnector 11A, 11B face the same direction (along axes parallel to eachother and spaced), located on the same side of the bridge connector.That makes it possible to connect the front of the connector bridge 11to the units positioned alongside as the first and second connectors11A, 11B face the front wall of the master unit 7 and the supplementaryunit 13 where the respective sockets are defined. This front position ofthe connector bridge 11 makes it possible to remove the connector bridge11, and pull out the master unit 7 or a supplementary unit 13, withoutmoving the other unit or the master unit 7 (that is to say, the onewhich must not be removed).

The bridge connector 11 comprises fastening elements associated with thefirst and the second connector 11A, 11B with retractable contacts. Morespecifically, fastening screws are coupled to holes defined in theconnector bridge 11 and are inserted in corresponding holes of the frontwall where the socket to which the connector 11A, 11B must be coupled isdefined, so as to guarantee the correct and stable connection of theconnector bridge 11.

Preferably, the connector bridge 11 is equipped with an LED visible fromthe outside, which light up and visually indicates when the bridgeconnector is connected.

Preferably, the first and the second connector 11A, 11B of the bridgeconnector 11 are connected rigidly, for example by means of a main body11C. Preferably, the first and the second connector 11A, 11B arepositioned at a mutual distance D1 which is greater than twice thedistance D2 which separates the first socket 7A or the second socket 7Bof the master unit 7 from an outer side wall 7D, 7E of the master unit7.

The supplementary unit 13 may be, for example, a further master unitprovided with its own network of slave units or an input/output moduleof the digital or analogue type or even a slave unit.

Preferably, the supplementary unit 13 has a first socket 13A and asecond socket 13B. For example, each of the sockets may comprise planarelectrical contacts or “pads” which can be coupled to respectiveretractable electrical contacts present in the multipolar connectors ofthe connector bridge 11. In an embodiment the supplementary unit 13 hasthe shape generically of a parallelepiped and the first socket 13A andthe second socket 13B are positioned on opposite sides of a front wall13C, respectively close to a first outer side wall 13D and a secondouter side wall 13E of the supplementary unit 13.

According to a preferred embodiment, the supplementary unit 13 has flatside walls 13D, 13E and a plurality of fins 17′ which protrude from theside walls 13D, 13E. Preferably, the fins 17 are parallel to each otherand arranged perpendicularly to a bottom wall 13T of the supplementaryunit 13. For example, the fins 17′ are oriented perpendicularly tofastening elements positioned on a back wall 13F of the supplementaryunit.

It should be noted that the fins 17, 17′ present on a side wall of themaster unit 7 and on a side wall of the supplementary unit 13 cooperateto form cooling ducts 14 arranged vertically which enhance dissipationof the hot air using the so-called “chimney or stack effect” to optimisethe heat exchange (that is, the cooling) of the master unit 7 and thesupplementary unit 13.

The supplementary unit is also preferably provided with fins at a topsurface.

In an embodiment, the multipolar cable 8 comprises at least a firstbundle of signal wires, which are intended for a correspondingcommunication channel and one or more power supply wires.

In an embodiment, the multipolar cable 8 defines a plurality ofcommunication channels, preferably of different rankings in terms ofspeed and complexity of the communication.

More specifically, the multipolar cable 8 preferably defines a firstcommunication channel (high ranking, for example Ethernet), a secondcommunication channel (intermediate ranking, for example CAN) and athird communication channel (low ranking, for example RS485).

In an embodiment, the multipolar cable 8 comprises a plurality of signalwires, for example four, for the first communication channel; aplurality of signal wires, for example two, for the second communicationchannel; a plurality of signal wires, for example, two, for the thirdcommunication channel.

The first channel is used, for example, for data transmission betweenthe slave units 6 and the master unit 7. The second channel is used, forexample, for transmitting data between the ancillary units 10 providedwith processing means and the master unit 7 of one or more slave units6. The third channel is used, for example, for transmitting triggersignals, that is, pulse signals constituting operational commandstransmitted by the master unit 7 to the slave units 6 or ancillary units10.

Moreover, preferably, the conducting multipolar cable 8 comprises one ormore wires for transmitting logic type signals.

Moreover, preferably, the multipolar cable 8 comprises one or more wiresfor distributing electrical power supply in the network of the system 1.

In an embodiment, the multipolar cable 8 comprises a plurality of powersupply wires (for example, three) at a first voltage value (for examplethe positive DC voltage of 24 V), and preferably a further plurality(for example, three) of reference power supply wires (for example GND ofthe 24 V DC).

The present invention also relates to a method for processing andtransmitting data between a numerical control unit 2 adapted to controla machine tool 3 and one or more devices present in the machine tool 3.

According to another aspect, the method comprises the following steps:

-   transferring operational signals from or to the devices through at    least one input channel 4;-   processing the operational signals to make control signals available    to the numerical control unit 2;-   arranging a network including a master unit 7 mounted in an electric    switchboard and at least one slave unit 6 connected to each other    through a multipolar cable 8;-   transferring the operational signals between the devices and the at    least one slave unit 6;

transferring data between the at least one slave unit 6 and the masterunit 7;

-   generating, by the master unit 7, a synchronization signal and    transmitting the synchronization signal through the multipolar cable    8, in order to synchronize a clock of the at least one slave unit 6    with a clock of the master unit 7.

The term “synchronization signal” may mean, for example, a data packetgenerated and transmitted inside the communication channel, for examplethe Ethernet network.

If the network comprises a plurality of slave units 6, the methodcomprises the following steps:

-   generating an alternating electric excitation signal by each of two    or more of the slave units 6 of the plurality in order to energize    measuring transducers of corresponding sensors connected to the    slave units 6;-   synchronizing the alternating electric excitation signals, based on    the synchronized clocks, by means of a correction of a relative    phase displacement between the alternating electric excitation    signals.

Preferably, the correction of a relative phase displacement between thealternating electric excitation signals is obtained by continuouslyvarying the clock frequency of the slave units 6.

Preferably, the alternating electric excitation signals are sinusoidsgenerated by processing a first and a second digital PWM (pulse widthmodulation) signals having suitable pulse-duration modulation. Morespecifically, the processing comprises a sum of the first and seconddigital signal PWM and a subsequent filtering.

Preferably, the method comprises one or more of the following steps:

-   assigning corresponding acquisition instants to data acquired by the    at least one slave unit 6;-   storing data relating to the corresponding operational signal in a    data packet for a certain time interval;-   transmitting the data packet to the master unit 7 through the    multipolar cable 8.

Preferably, if the network comprises a plurality of slave units 6, themethod comprises the following steps:

-   dividing a data transmission time interval into a plurality of time    slots and uniquely assigning to each slave unit 6 a corresponding    time slot of the plurality of time slots, by the master unit 7;-   transmitting data through the multipolar cable 8 within the    respective time slot by each slave unit 6.

In an embodiment, the method comprises a configuration step. During theconfiguration step, the master unit 7 transmits a configuration signalthrough the multipolar cable 8, to define a unique identification codeassigned to the at least one slave unit 6 and to store the code in thememory of the master unit 7.

According to a preferred embodiment, in a network which comprises theslave units 6 which are connected in series and each have at least oneswitch positioned facing away from the master unit 7, the configurationstep comprises a step of assigning to each slave unit 6 a uniqueidentification code, with the following steps:

-   transmission by the master unit 7 through the multipolar cable 8 of    a configuration signal to the first slave unit 6 of the series among    the slave units 6 which are still without a unique identification    code;-   receiving the configuration signal by the slave unit 6, the switch    being open;-   transmission of a response signal from the slave unit 6 to the    master unit 7, in response to the configuration signal;-   transmission by the master unit 7 to the slave unit 6 of an    assignment signal for setting a unique identification code to the    slave unit 6 and to change switch from open to closed; and-   repeating the previous steps for all the other slave units 6 which    are still without a unique identification code, until the master    unit 7 has assigned to each unit a respective unique identification    code.

In an embodiment, the step of arranging the network comprises connectingtwo or more slave units 6 connecting the second socket 6C of a slaveunit 6 and the first socket 6B of another slave unit 6.

The mutual connection of two slave units 6 may be performed byconnecting directly the respective sockets or by using the multipolarcable 8.

In an embodiment, the step of arranging the network comprises connectingat least one slave unit 6 to one or two ancillary units 10 provided witha first socket 10A and a second socket 10B. The first and second socket10A, 10B of each ancillary unit 10 is configured to be coupled to afirst or a second connector of the multipolar connectors 9 and to one ofthe first and second sockets 6B, 6C of the slave unit 6. Preferably, anoperation of the ancillary unit 10 is controlled by an operation of theslave unit 6 to which it is connected.

If the multipolar cable 8 comprises two or more pieces, each having afirst and a second end provided with a multipolar connector 9, themutual connection of two slave units 6 is carried out by means of one ofthe pieces.

Preferably, the step of arranging the network comprises making aconfiguration of the “daisy chain” type.

In an embodiment, the arrangment of the network comprises making abranch, with respect to the configuration of the “daisy chain” type,through a multipolar connector coupled to one of the multipolarconnectors 9 of the multipolar cable 8 and/or connected to the first orthe second socket 6B, 6C of the slave unit 6.

According to an alternative embodiment, the step of arranging thenetwork comprises connecting a first unit to a second unit, that is tosay the master unit 7 to a supplementary unit 13 provided with at leastone socket 13A through a bridge connector 11 having a first connector11A and a second connector 11B which can be coupled to the first or tothe second socket 7A, 7B of the master unit 7.

Preferably, the connector bridge 11 is rigid and U-shaped with the twomultipolar connectors 11A, 11B placed at the ends.

If the master unit 7 and the supplementary unit 13 each have a first anda second socket (each socket is configured to be coupled to a multipolarconnector), the electrical connection of the master unit 7 to thesupplementary unit 13 comprises coupling the bridge connector 11 to oneof the sockets 7A, 7B of the master unit 7 and to one of the sockets13A, 13B of the supplementary unit 13.

If the master unit 7 and the supplementary unit 13 are each slidablyconnectable to a supporting or mounting bar (for example a DIN rail) ofan electrical panel, the method comprises a step of connecting themaster unit 7 and the supplementary unit 13 to the same supporting bar.Preferably, the master unit 7 and the supplementary unit 13 arepositioned alongside of each other. Subsequently, the master unit 7 andthe supplementary unit 13 are connected electrically by means of thebridge connector 11. More specifically, in the preferred embodimentwherein the multipolar connectors are comprise retractable contacts, theelectrical connection comprises positioning the bridge connector 11 insuch a way that the retractable contacts touch corresponding planarelectrical contacts of the sockets of the master unit 7 and thesupplementary unit 13, and defining and fixing the position of thebridge connector 11 with respect to to the master unit 7 and thesupplementary unit 13 by means of fastening elements.

A step of disconnecting, for example to replace a supplementary unit 13alongside the master unit 7, comprises removing the fastening elementsand unplugging the bridge connector 11 to detach the retractablecontacts of the bridge connector 11 from the planar electrical contactsof the sockets of the two units, and removing the unit to be replaced,for example the supplementary unit 13, pulling it from the front withoutthe need to move the master unit 7. This is particularly advantageouswhen there are several units side by side and electrically connected byconnector bridges, and a unit flanked by other units is to be replaced.

The steps for electrical connection and disconnection are part of amethod for managing electrical connections according to the invention,which is generally applicable to measuring and/or checking systems.

Preferably, the network comprises at least one slave unit 6 positionedin the work space 3C of the machine tool 3. The master unit 7 and anysupplementary unit(s) 13 are generally positioned in an electricalpanel.

If the system 1 comprises a plurality of slave units 6, in anembodiment, the method comprises the steps of:

-   dividing a data transmission time interval into a plurality of time    slots and uniquely assigning to each slave unit 6 a corresponding    time slot of the plurality of time slots, by the master unit 7;-   transferring data from the slave unit 6 to the master unit 7,    through the multipolar cable 8, in which the data is transferred    from each slave unit 6 only within the respective time slot.

The method preferably comprises the following steps:

-   assigning, by the master unit 7, a unique identification code    associated with each slave unit 6;-   performing, by the master unit 7, a continuous data collection cycle    in which, at each time slot of the data transmission time interval,    the master unit 7 receives and stores the data transmitted by the    corresponding slave unit 6 and associates the date with the slave    unit 6 from which the data come from.

Preferably, the data transmission time interval is divided into a numberof time slots greater than the number of slave units 6 of the system 1,to keep at least one additional or extra time slot (as well as the timeslots assigned to the slave units 6) which may be used by the masterunit 7 to set parameters, during the continuous data collection cycle,the slave units 6.

It should be noted that, preferably, the data transmission, theelectrical power supply of slave unit 6 and the synchronization of theclock of each slave unit 6 with the clock of the master unit 7 arecarried out by means of the multipolar cable 8.

In an embodiment, the method comprises a step of acquiring and storing,by the slave unit 6, data corresponding to at least one operationalsignal received through the input channel 4 (that is, the port 6A) and astep of assigning corresponding acquisition instants to the dataacquired.

The method also comprises a step of detecting or collecting, by themaster unit 7, at least one power supply parameter (voltage or current,for example) representing the electrical current draw in the entiresystem, in only the master unit 7 or in each slave unit 6.

Alternatively or in addition, the method also comprises a step forcollecting, by the master unit 7, an internal temperature of one or more(preferably all) the slave units 6 and/or the master unit 7.

Preferably, the master unit 7 detects or collects one or more of thefollowing parameters for the slave units 6 and/or for the master unit 7:supply voltage, electrical current draw, absorbed power.

In an embodiment, the method comprises a step of comparing detectedparameters of power supply and/or internal temperature with referencevalues. Preferably, the method also comprises a step of generating alarmsignals as a function of such comparison.

Preferably, the at least one slave unit 6 transfers in synchrony to themaster unit 7 data relating to the operational signals and data relatingto the power supply parameter and/or to the internal temperature.

In an embodiment, the multipolar cable 8 has at least one connector lessend, that is one end without a connector (a free end).

A method according to the present invention to connect, in a genericmeasuring and/or checking system, at least a first and a second unitusing the multipolar cable 8 comprises the following steps:

-   -   positioning the multipolar cable;    -   coupling a fast wiring multipolar connector to the end of the        multipolar cable without connector; and    -   coupling the fast wiring multipolar connector to one of the        first and second units.

According to a preferred application, where the measuring and/orchecking system is applied to a machine tool, the step of positioningthe multipolar cable comprises the insertion of the end without aconnector in a machine cable carrying duct of the machine tool 3 and,after the insertion, a step of coupling a fast wiring multipolarconnector 12 to the free end.

Preferably, the coupling of the fast wiring multipolar connector 12 tothe free end of the multipolar cable 8 comprises a step of perforatingthe insulating sheath which covers the sheathed wires 8A contained inthe multipolar cable 8, by means of perforating electrical contacts 12Ppresent in the fast wiring multipolar connector 12.

The fast wiring multipolar connector 12 is then connected to the masterunit 7. The master unit 7 is positioned in the space 3D of theelectrical panel. The end with a pre-assembled multipolar connector ofthe multipolar cable 8 is positioned in the work space 3C.

The end with a pre-assembled multipolar connector of the multipolarcable 8 is connected to a slave unit 6. Preferably, other slave units 6and/or ancillary units 10 are connected to the slave unit 6, eitherdirectly or by means of further pieces of multipolar cable 8.Preferably, other slave units 6 and/or ancillary units 10 are positionedin the work space 3C of the machine tool 3.

1. A data processing and transmission system for a numerical controlunit adapted to control a machine tool, comprising: at least one inputchannel adapted to a transmit operational signals from or to devicespresent in the machine tool; electronic circuits configured to processsaid operational signals to make available on an output interface,control signals for the numerical control unit, wherein the dataprocessing and transmission system comprises: a multipolar cable havinga first and a second end, each end provided with a multipolar connector;a master unit having said output interface, a main processor, a memoryand at least one socket configured to be coupled to one of themultipolar connectors; one or more slave units, each slave unit providedwith at least one external port defining said input channel, a memory, asecondary processor, and provided with a first socket and a secondsocket, configured to be coupled at least to a first or a secondconnector of said multipolar connectors in order to interconnect theslave unit at least with the master unit, wherein the master unit has aclock and each slave unit has a clock, and wherein the main processor isprogrammed to generate a synchronization signal and to transmit saidsynchronization signal through the multipolar cable in order tosynchronize all the clocks of the slave units with the clock of themaster unit.
 2. The system according to claim 1, wherein each slave unitreceives the synchronization signal as it is generated by the masterunit and synchronizes its own clock independently from the other slaveunits.
 3. The system according to claim 1, wherein two or more of theslave units comprise an electronic circuit for generating an alternatingelectric excitation signal, and all the alternating electric excitationsignals are synchronized in time with each other.
 4. The system (1)according to claim 3, wherein each of said two or more slave units isprogrammed to transmit as output the alternating electric excitationsignal through said at least one external port, in order to excite acorresponding measuring transducer including a variable inductivecoupling.
 5. The system (1) according to claim 3, wherein each of saidtwo or more slave units comprises: a generator of a first and a seconddigital PWM (pulse width modulation) signal; and processing circuitsadapted to receive the first and second digital PWM signals and toprocess them to generate the alternating electric excitation signalconsisting of a sinusoid.
 6. The system according to claim 3, wherein,for each of said two or more slave units the electronic circuit forgenerating the alternating electric excitation signal is configured tocorrect the alternating electric excitation signal in phase, atpredetermined regular time intervals, in order to synchronize it inphase with another alternating electric excitation signal generated byanother slave unit.
 7. The system according to claim 6, wherein the mainprocessor is programmed to continuously vary the frequency of the clocksof the slave units in order to correct the alternating electricexcitation signal in phase.
 8. The system according to claim 1, whereineach of said one or more slave units is configured to acquire throughthe external port at least one operational signal comprising data and tostore it, and is programmed to assign corresponding acquisition instantsto said data acquired through the external port, based on its own clock.9. The system according to claim 1, wherein each of said one or moreslave units is programmed to store for a certain time interval dataacquired through said at least one external port, collecting the data ina data packet, and to transmit at least said data packet to the masterunit through the multipolar cable.
 10. The system according to claim 1,wherein the multipolar cable comprises: at least a first bundle ofsignal wires for a corresponding communication network; and one or morepower wires.
 11. A method for processing and transmitting data between anumerical control unit adapted to control a machine tool, and one ormore devices present in the machine tool, the method comprising thefollowing steps: transferring operational signals from or to saiddevices through at least one input channel; processing the operationalsignals to make control signals available to the numerical control unit;wherein the method comprises the following steps: arranging a networkincluding a master unit mounted in an electric switchboard and at leastone slave unit the at least one slave unit and the master unit areconnected to each other through a multipolar cable; transferring theoperational signals between the devices and the at least one slave unit;transferring data between said at least one slave unit and said masterunit; generating a synchronization signal by the master unit andtransmitting said synchronization signal through the multipolar cable inorder to synchronize a clock of said at least one slave unit with aclock of the master unit.
 12. The method according to claim 11, whereineach slave unit receives the synchronization signal as it is generatedby the master unit and synchronizes its own clock independently from theother slave units.
 13. The method according to claim 11, wherein thenetwork comprises a plurality of slave units, the plurality of slaveunits being connected through the multipolar cable, the methodcomprising the following steps: generating an alternating electricexcitation signal by each of two or more of the slave units of theplurality in order to excite measuring transducers of correspondingsensors connected to said slave units; synchronizing said alternatingelectric excitation signals, based on said synchronized clocks, by meansof a correction of a relative phase displacement between the alternatingelectric excitation signals.
 14. The method according to claim 13,wherein the correction of a relative phase displacement between thealternating electric excitation signals is obtained by continuouslyvarying the clock frequency of the slave units.
 15. The method accordingto claim 13, wherein said alternating electric excitation signals aresinusoids generated by processing a first and a second digital PWM(pulse width modulation) signals, said processing comprising a sum ofthe first and second digital PWM signals followed by a filtering. 16.The method according to claim 11, comprising a step of assigningcorresponding acquisition instants to data acquired by said at least oneslave unit.
 17. The method according to claim 11, comprising thefollowing steps, performed by the at least one slave unit: storing datarelating to the corresponding operational signal in a data packet for acertain time interval; and transmitting the data packet to the masterunit through the multipolar cable.
 18. The method according to claim 11,comprising a configuration step, wherein the master unit transmits aconfiguration signal through the multipolar cable to define a uniqueidentification code assigned to the at least one slave unit and to storethe unique identification code in the memory of the master unit.
 19. Themethod according to claim 11, wherein the multipolar cable connectingthe master unit and said at least one slave unit to each othercomprises: at least a first bundle of signal wires, intended for acorresponding communication network; and one or more power wires.